1. Field of the Invention
The present invention relates to an aerial optical fiber cable, wherein one or more loose tubes enclosing optical fibers are accommodated within respective grooves formed on a non-conductive slot around which a plurality of strength members are arranged.
2. Description of the Related Art
Generally, aerial optical fiber cables to be deployed by suspending between steel towers and/or utility poles must have excellent mechanical and environmental characteristics to survive the hostile environments (such as wind, rain, snow, lightning, and temperature extremes). As mentioned above, the aerial optical fiber cables are installed by suspending between power transmission towers and/or utility poles.
An exemplary aerial optical fiber cable may comprise a central strength member serving as a central core as well as a central support member, and a plurality of loose tubes around the central strength member, wherein the loose tubes each enclose one or more optical fibers.
Further, the entire outer circumference enclosing all the loose tubes is wrapped with outer shell tapes for preventing moisture penetration. A void space between the outer shell tapes and the central strength member is filled with a filling compound. The outside of the outer shell tape is cladded with a first polyethylene sheath layer for protecting the cable from the adverse environmental conditions. The first polyethylene sheath layer is covered with strength members in order to protect the optical fiber cables from damage caused by the hostile environmental conditions and by the external forces. The outer circumference of the strength members is cladded with a second polyethylene sheath layer for further protecting the above cable component parts against the external adverse environment conditions.
Accordingly, in the above structure of the exemplary aerial optical fiber cable, when the cable is subjected to severe external forces and/or hostile environmental conditions, the strength members and the first and second polyethylene sheath layers slip on each other due to a low friction coefficient, thereby causing damage to the optical fiber cable. And since the strength members are cladded with the polyethylene material, when the cable is exposed to a high temperature, the mechanical strength of the strength members is deteriorated, and hence the adhesive force of the clamp for fixing the optical fiber cable on the power transmission towers and utility poles decreases, resulting in separation of the optical fiber cable from the power transmission towers and utility poles.